Improving the electrochemical performance of LiFePO4 cathode with novel water-soluble binders.

To maintain the integrity of electrodes via conductive binders plays a critical role for Li-ion batteries. In this letter, polyaspartic acid (PASP) was synthesized and used as a novel water-soluble binder for an LiFePO 4 (LFP) cathode. At a 1 C current density, this LiFePO 4 cathode had a discharge specific capacity of 152 mAh g−1 and retained close to 100% of the initial specific capacity after 40 cycles. Furthermore, this LiFePO4 cathode also maintained a high specific capacity of 122 mAh g−1 at 5C rate. The results of electrochemical impedance spectroscopy and scanning electron microscopy indicated that the layer of PASP that was coated on the LFP electrode, which maintained the integrity of the conductive network and reduced the Li + diffusion path length of the LFP electrode. Based on these properties, PASP could be a prospective binder for LFP cathodes. [Display omitted] • PASP contains both nonpolar and polar groups. And PASP is a fluorine-free binder. • PASP as water-based binder is safe, environmentally friendly for LFP cathnod. • PASP is on the LFP particle to maintained the integrity of the conductive network. [ABSTRACT FROM AUTHOR]